Flame insulative silicone compositions

Claim 2

A flame insulative room temperature vulcanizable silicone rubber composition comprising (a) 100 parts by weight of silanol end-stopped diorganopolysiloxane having a viscosity varying from 1,000 to 200,000 centipoise viscosity at 25° C.; (b) from 50 to 300 parts by weight of an inert filler selected from the class consisting of fumed silica and precipitated silica; (c) from 25 to 150 parts by weight of glass frits; (d) from 1 to 15 parts by weight of a silicate having the formula, R.sub.a.sup.1 Si(OR.sup.2).sub.4-a and partial hydrolysis products thereof, where R 1 and R 2 are selected from monovalent hydrocarbon radicals and halogenated monovalent hydrocarbon radicals, a is 0 or 1, and (e) from 0.01 to 5 parts by weight of the metal salt of a carboxylic acid the metal varying from lead to manganese in the Periodic Table.

Claim 3

The composition of claim 1 wherein the silanol end-stopped diorganopolysiloxane has the formula, ##STR3## where R 4 is selected from the class consisting of alkyl radicals, aryl radicals, alkenyl radicals and fluorinated alkyl radicals of up to 10 carbon atoms and b varies from 380 to 2,000.

Claim 4

The composition of claim 1 wherein there is further present from 5 to 50 parts by weight of glass fibers.

Claim 5

The composition of claim 3 wherein said glass fibers are present at a concentration of 5 to 30 parts by weight and are milled glass fibers having an average size varying from 0.01 to 0.5 inches.

Claim 6

The composition of claim 4 wherein said glass frits has a size varying from 50 microns to 400 microns.

Claim 7

The composition of claim 5 wherein the amount of said glass frits varies from 50 to 100 parts by weight.

Claim 8

The composition of claim 6 wherein there is present from 5 to 10 parts of carbon black.

Claim 9

The composition of claim 1 wherein said inert filler is selected from the class consisting of ground silica, fumed silica and precipitated silica.

Claim 10

A process for forming a flame insulative room temperature vulcanizable silicone rubber composition comprising mixing at room temperature in the presence of ambient moisture (a) 100 parts by weight of a silanol end-stopped diorganopolysiloxane having a viscosity varying from 1,000 to 200,000 centipoise at 25° C., where the organo groups are selected from the class of monovalent hydrocarbon radicals and halogenated monovalent hydrocarbon radicals; (b) from 50 to 300 parts by weight of an inert filler selected from the class consisting of fumed silica and precipitated silica; (c) from 25 to 150 parts by weight of glass frits; (d) from 1 to 15 parts by weight of a silicate having the formula, R.sub.a.sup.1 Si(OR.sup.2).sub.4-a and partial hydrolysis products thereof where R 1 and R 2 are selected from monovalent hydrocarbon radicals and halogenated monovalent hydrocarbon radicals, a is 0 or 1 and (e) from 0.01 to 5 parts by weight of the metal salt or a carboxylic acid the metal varying from lead to manganese in the Periodic Table.

Claim 11

A process for forming a flame insulative room temperature vulcanizable silicone rubber composition comprising mixing at room temperature in the presence of ambient moisture (a) 100 parts by weight of a silanol end-stopped diorganopolysiloxane having a viscosity varying from 1,000 to 200,000 centipoise at 25° C., where the organo groups are selected from the class of monovalent hydrocarbon radicals and halogenated monovalent hydrocarbon radicals; (b) from 50 to 300 parts by weight of an inert filler selected from the class consisting of fumed silica and precipitated silica; (c) from 25 to 150 parts by weight of glass frits; (d) from 1 to 15 parts by weight of a silicate having the formula, R.sub.a.sup.1 Si(OR.sup.2).sub.4-a and partial hydrolysis products thereof where R 1 and R 2 are selected from monovalent hydrocarbon radicals and halogenated monovalent hydrocarbon radicals, a is 0 or 1 and (e) from 0.01 to 5 parts by weight of the metal salt or a carboxylic acid the metal varying from lead to manganese in the Periodic Table.